Sending custom data with a push from iOS Swift app

Question:

I pass JSON in the data parameter of /createMessage, the push is delivered, but the custom data never arrives and /getMessageDetails shows data = <null>. Why?

Answer:

The request is structured incorrectly. data (like devices and users) belongs inside the object in the notifications array, not next to application/auth. Anything placed at the request root is ignored.

Correct Swift example:

let urlString = "https://api.pushwoosh.com/json/1.3/createMessage"

let parameters: [String: Any] = [
    "request": [
        "application": "ABCDE-12345",
        "auth": "YOUR_API_TOKEN",
        "notifications": [[
            "send_date": "now",
            "content": "Click to OK your payment",
            "devices": ["qwertyuiop1234567890"],
            "data": ["retailerUserid": "25"]
        ]]
    ]
]

Notes:

• The API host is api.pushwoosh.com (or <APP_CODE>.api.pushwoosh.com). The old cp.pushwoosh.com host no longer serves the API.
• data is delivered to the device in the u payload key (exposed as userdata by the SDKs).
• /createMessage is deprecated — new integrations should use Messaging API v2.

See Messages API and Using custom data.